It's good to hear from you again! We don't have plans for adding a JIT/Wasm
backend for RISC-V at this point. Most of SpiderMonkey (except Wasm
support) should work without it, it's just slower without JITs. Making sure
a --disable-jit build of Firefox works on RISC-V would be a good first step.
We could _potentially_ have a community-maintained JIT/Wasm backend for
RISC-V, like our MIPS code, but this would also depend on the impact to
other parts of the code base and whether the community is willing to
actively maintain it going forward.
Adding a JIT backend is a big project. We'd be happy to answer questions
and give feedback though. You can also find us in the #spidermonkey room on
> dev-tech-js-engine-internals mailing list